...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Physical Oceanography >Symmetric Instability in Cross-Equatorial Western Boundary Currents
【24h】

Symmetric Instability in Cross-Equatorial Western Boundary Currents

机译：交叉赤道西部边界电流中的对称不稳定性

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The upper limb of the Atlantic meridional overturning circulation draws waters with negative potential vorticity from the Southern Hemisphere into the Northern Hemisphere. The North Brazil Current is one of the cross-equatorial pathways in which this occurs: upon crossing the equator, fluid parcels must modify their potential vorticity to render them stable to symmetric instability and to merge smoothly with the ocean interior. In this work a linear stability analysis is performed on an idealized western boundary current, dynamically similar to the North Brazil Current, to identify features that are indicative of symmetric instability. Simple two-dimensional numerical models are used to verify the results of the stability analysis. The two-dimensional models and linear stability theory show that symmetric instability in meridional flows does not change when the nontraditional component of the Coriolis force is included, unlike in zonal flows. Idealized three-dimensional numerical models show anticyclonic barotropic eddies being spun off as the western boundary current crosses the equator. These eddies become symmetrically unstable a few degrees north of the equator, and their PV is set to zero through the action of the instability. The instability is found to have a clear fingerprint in the spatial Fourier transform of the vertical kinetic energy. An analysis of the water mass formation rates suggest that symmetric instability has a minimal effect on water mass transformation in the model calculations; however, this may be the result of unresolved dynamics, such as secondary Kelvin-Helmholtz instabilities, which are important in diabatic transformation.
机译：大西洋经络倾覆循环的上肢向南半球南半球的负势涡度带来水域。北巴西电流是这种情况发生的跨赤道途径之一：穿过赤道时，流体包裹必须改变它们的潜在涡度，以使它们稳定对对称的不稳定并与海洋内部顺利合并。在这项工作中，在理想的西部边界电流，动态类似于北巴西电流的情况下执行线性稳定性分析，以识别指示对称不稳定性的特征。简单的二维数值模型用于验证稳定性分析的结果。二维模型和线性稳定性理论表明，当包括在区间流动的情况下包括科里奥利力的非传统组分时，子午流中的对称不稳定性不会改变。理想化的三维数值模型显示，当西边界电流穿过赤道时，旋转的反速度波波波托特·埃德迪。这些eddies在赤道的北方几度北方变得对称地不稳定，并且通过不稳定性的动作，它们的PV设置为零。发现不稳定性在垂直动能的空间傅里叶变换中具有清晰的指纹。水质量形成率分析表明对称不稳定性对模型计算中的水质转化具有最小的影响;然而，这可能是未解决的动态的结果，例如次级开尔文 - 亥姆霍茨稳定性，这在糖尿病转化中是重要的。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号